1. Field of the Invention
The present invention generally relates to an attachment structure. More specifically, the present invention relates to an attachment structure of a drag control member of a lever drag reel that adjusts a drag force of a drag mechanism.
2. Background Information
A lever-drag reel is known to have a reel that is capable of adjusting drag force by moving a spool shaft in an axial direction by a drag control member that is pivotably attached on the spool shaft. (See, for example, Japanese Publication No. H11-9157.) A base end of this of type drag control member is pivotably supported by a pivot support portion that is formed in a cover member of a reel unit so as to concentrically protrude with the spool shaft. In addition, the base end of the drag control member is provided with a cam mechanism that moves in the axial direction in response to its pivoting. The cam mechanism has a first cam provided in the drag control member and a second cam that engages with the first cam. The second cam moves in a direction of the pivot axis (spool shaft) in response to the pivoting of the drag control member. A guiding portion for non-rotatably and axially movably mounting the second cam is provided in an inner periphery side of the pivot support portion of the reel unit. In order to distributively receive the force of the rotary direction on a number of surfaces, the guiding portion is integrally formed in a hexagonal appearance on the inner periphery side of the pivot support portion with the pivot support portion.
In the case where the cover member of the reel unit is formed by forging, the guiding portion, with the hexagonal appearance, is formed at the same time in formation of the cover member. However, in the case where the reel unit such as the cover member is formed in a metal machining process, the cost of processing is high when the guide member is formed integrally with it by a cutting process. Accordingly, it is conceivable to fasten the guiding portion that is formed separately from the reel unit to the reel unit by crimp fastening. In this case, since the guiding portion should non-rotatably guide the second cam, it is necessary to non-rotatably fasten the guiding portion to the reel unit. Accordingly, it is conceivable to non-rotatably fasten the guiding portion to the reel unit by using the hexagonal appearance. In this case, a hexagonal recessed portion is formed and the guiding portion engages with it. When the hexagonal recessed portion is formed by a machining process with a tool, it is difficult to form a precise hexagon since such a tool for forming the recessed portion is a cylindrical tool (e.g. end mill). For this reason, the number of contact parts between an inner peripheral surface of the recessed portion and an outer periphery surface of the guiding portion varies and is unstable. When the number of these contact parts decreases, a load is concentratedly applied in proximity to a corner of the hexagonal shape. Thus, the part deforms. This may cause wobbling of the fastened part.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved drag control member attachment structure to reduce variation of contact parts between a hexagonal guiding portion and a reel unit. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.